package com.lichao.watermark.streams_join;

import org.apache.flink.api.common.eventtime.SerializableTimestampAssigner;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.api.common.functions.CoGroupFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.util.Collector;

// 基于窗口的 join
public class CoGroupExample {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        DataStream<Tuple2<String, Long>> stream1 = env.fromElements(
                Tuple2.of("a", 1000L),
                Tuple2.of("b", 1000L),
                Tuple2.of("a", 2000L),
                Tuple2.of("b", 2000L)
        ).assignTimestampsAndWatermarks(WatermarkStrategy.<Tuple2<String, Long>>forMonotonousTimestamps()
                .withTimestampAssigner(
                        new SerializableTimestampAssigner<Tuple2<String, Long>>() {
                            @Override
                            public long extractTimestamp(Tuple2<String, Long> stringLongTuple2, long l) {
                                return stringLongTuple2.f1;
                            }
                        }
                )
        );

        DataStream<Tuple2<String, Long>> stream2 = env.fromElements(
                Tuple2.of("a", 3000L),
                Tuple2.of("b", 3000L),
                Tuple2.of("a", 4000L),
                Tuple2.of("b", 4000L)
        ).assignTimestampsAndWatermarks(
                WatermarkStrategy.<Tuple2<String, Long>>forMonotonousTimestamps()
                        .withTimestampAssigner(
                                new SerializableTimestampAssigner<Tuple2<String, Long>>() {
                                    @Override
                                    public long extractTimestamp(Tuple2<String, Long> stringLongTuple2, long l) {
                                        return stringLongTuple2.f1;
                                    }
                                }
                        )
        );

        stream1.coGroup(stream2)
                .where(r -> r.f0)
                .equalTo(r -> r.f0)
                .window(TumblingEventTimeWindows.of(Time.seconds(5)))
                .apply(new CoGroupFunction<Tuple2<String, Long>, Tuple2<String, Long>, String>() {
                    @Override
                    public void coGroup(Iterable<Tuple2<String, Long>> iter1,
                                        Iterable<Tuple2<String, Long>> iter2, Collector<String> collector) throws Exception {
                        collector.collect(iter1 + "=>" + iter2);
                    }
                })
                .print();
        env.execute();
    }
}